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[WIP] recreate the tsc crash we're seeing in mongosh #551

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155 changes: 155 additions & 0 deletions packages/mql-typescript/tests/real.ts
Original file line number Diff line number Diff line change
@@ -0,0 +1,155 @@
/* eslint-disable @typescript-eslint/no-unused-vars */
import type * as schema from '../out/schema';
import type { Document } from 'bson';

interface GenericCollectionSchema {
schema: Document;
}
interface GenericDatabaseSchema {
[key: string]: GenericCollectionSchema;
}
interface GenericServerSideSchema {
[key: string]: GenericDatabaseSchema;
}
type StringKey<T> = keyof T & string;

class Mongo<M extends GenericServerSideSchema = GenericServerSideSchema> {}

type CollectionWithSchema<
M extends GenericServerSideSchema = GenericServerSideSchema,
D extends GenericDatabaseSchema = M[keyof M],
C extends GenericCollectionSchema = D[keyof D],
N extends StringKey<D> = StringKey<D>,
> = Collection<M, D, C, N> & {
[k in StringKey<D> as k extends `${N}.${infer S}` ? S : never]: Collection<
M,
D,
D[k],
k
>;
};

class Collection<
M extends GenericServerSideSchema = GenericServerSideSchema,
D extends GenericDatabaseSchema = M[keyof M],
C extends GenericCollectionSchema = D[keyof D],
N extends StringKey<D> = StringKey<D>,
> {
_mongo: Mongo<M>;
_database: DatabaseWithSchema<M, D>;
_name: N;
constructor(
mongo: Mongo<M>,
database: DatabaseWithSchema<M, D> | Database<M, D>,
name: N,
) {
this._mongo = mongo;
this._database = database as DatabaseWithSchema<M, D>;
this._name = name;
}
getName(): N {
return this._name;
}
async find(
query?: schema.Query<C['schema']>,
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Changing C['schema'] here (and in the return type) to Document does not crash.

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Similarly changing schema.Query to just be any here does not crash.

Anything more complicated than that breaks.

projection?: Document,
options: Document = {},
): Promise<schema.Query<C['schema']> | undefined> {
return Promise.resolve(query);
}
}

type DatabaseWithSchema<
M extends GenericServerSideSchema = GenericServerSideSchema,
D extends GenericDatabaseSchema = GenericDatabaseSchema,
> = Database<M, D> & {
[k in StringKey<D>]: Collection<M, D, D[k], k>;
};

function isValidCollectionName(name: string): boolean {
return !!name && !/[$\0]/.test(name);
}

export class Database<
M extends GenericServerSideSchema = GenericServerSideSchema,
D extends GenericDatabaseSchema = GenericDatabaseSchema,
> {
_mongo: Mongo<M>;
_name: StringKey<M>;
_collections: Record<StringKey<D>, CollectionWithSchema<M, D>>;

constructor(mongo: Mongo<M>, name: StringKey<M>) {
this._mongo = mongo;
this._name = name;
const collections: Record<
string,
CollectionWithSchema<M, D>
> = Object.create(null);
this._collections = collections;

const proxy = new Proxy(this, {
get: (target, prop): any => {
if (prop in target) {
return (target as any)[prop];
}

if (
typeof prop !== 'string' ||
prop.startsWith('_') ||
!isValidCollectionName(prop)
) {
return;
}

if (!collections[prop]) {
collections[prop] = new Collection<M, D>(
mongo,
proxy,
prop,
) as CollectionWithSchema<M, D>;
}

return collections[prop];
},
});
return proxy;
}

getCollection<K extends StringKey<D>>(
coll: K,
): CollectionWithSchema<M, D, D[K], K> {
const collection = new Collection<M, D, D['myCollection']>(
this._mongo,
this,
'myCollection',
);

return collection as CollectionWithSchema<M, D, D[K], K>;
}
}

async function run() {
const serverSchema = {
myDatabase: {
myCollection: {
schema: {
_id: 'ObjectId',
name: 'string',
age: 'number',
},
},
},
};
const mongo = new Mongo<typeof serverSchema>();
const db = new Database<
typeof serverSchema,
(typeof serverSchema)['myDatabase']
>(mongo, 'myDatabase') as DatabaseWithSchema<
typeof serverSchema,
(typeof serverSchema)['myDatabase']
>;
const query = await db.myCollection.find({ name: 'foo' });
console.log(query);
}

run().catch(console.error);